On September 7, 2000, in the framework of the UN Millennium Summit, the Presidents of Ukraine and Sierra Leone met. The parties discussed issues of bilateral cooperation, in particular in the military-technical sphere.

On October 13, 2016, the Deputy Minister of Economic Development and Trade of Ukraine - Trade Representative of Ukraine N. Mykolska met with members of the Sierra Leone delegation headed by the Minister of Agriculture, Forestry and Food Protection of the Republic of Sierra Leone Monty Patrick Jones in Kyiv.

As part of Ukraine's commitments as a UN member state, Presidential Decree №1319 / 2000 of December 8, 2000 sent a peacekeeping contingent of up to 800 servicemen and a helicopter detachment to the UN Mission in Sierra Leone. Armed Forces of Ukraine. The decree also provided for the provision of material and technical resources to the UN in the total amount of up to 220 armored personnel carriers and up to 220 trucks of the Armed Forces of Ukraine and services to ensure their use in the UN international peacekeeping operation in Sierra Leone. According to the UN Secretariat, the participation of the Ukrainian contingent was one of the decisive factors in the implementation of the UN operation in this country. His work has been repeatedly praised by the Mission's leadership. The Ukrainian contingent completed its work in Sierra Leone in February 2005. 

The Republic of Sierra Leone supported the resolution of the UN General Assembly of March 27, 2014 / №68 / 262 "Territorial integrity of Ukraine". 

Sierra Leone abstained from voting for the resolution of the UN General Assembly "Situation of human rights in the Autonomous Republic of Crimea and in the city of Sevastopol" in December 2017, (in December 2018 and December 2020 did not participate) and in December 2021.

The Sierra Leonian delegation did not participate in the voting  for the UN General Assembly resolution "The problem of militarization of the Autonomous Republic of Crimea and Sevastopol, Ukraine, as well as parts of the Black and Azov Seas." in December 2019, in December 2020 and in December 2021.